#define BLEND_NONE 0
#define BLEND_NORMAL 1
#define BLEND_DOMINANT 2
#define LUMINANCE_WEIGHT 1.0
#define EQUAL_COLOR_TOLERANCE 30.0/255.0
#define STEEP_DIRECTION_THRESHOLD 2.2
#define DOMINANT_DIRECTION_THRESHOLD 3.6

#if __VERSION__ >= 130
#define COMPAT_VARYING in
#define COMPAT_TEXTURE texture
out vec4 FragColor;
#else
#define COMPAT_VARYING varying
#define FragColor gl_FragColor
#define COMPAT_TEXTURE texture2D
#endif

#ifdef GL_ES
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;
uniform sampler2D Texture;
COMPAT_VARYING vec4 TEX0;
COMPAT_VARYING vec4 t1;
COMPAT_VARYING vec4 t2;
COMPAT_VARYING vec4 t3;
COMPAT_VARYING vec4 t4;
COMPAT_VARYING vec4 t5;
COMPAT_VARYING vec4 t6;
COMPAT_VARYING vec4 t7;

// fragment compatibility #defines
#define Source Texture
#define vTexCoord TEX0.xy

#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
#define outsize vec4(OutputSize, 1.0 / OutputSize)

	const float  one_sixth = 1.0 / 6.0;
	const float  two_sixth = 2.0 / 6.0;
	const float four_sixth = 4.0 / 6.0;
	const float five_sixth = 5.0 / 6.0;

	float reduce(const vec3 color)
	{
		return dot(color, vec3(65536.0, 256.0, 1.0));
	}
	
	float DistYCbCr(const vec3 pixA, const vec3 pixB)
	{
		const vec3 w = vec3(0.2627, 0.6780, 0.0593);
		const float scaleB = 0.5 / (1.0 - w.b);
		const float scaleR = 0.5 / (1.0 - w.r);
		vec3 diff = pixA - pixB;
		float Y = dot(diff, w);
		float Cb = scaleB * (diff.b - Y);
		float Cr = scaleR * (diff.r - Y);
		
		return sqrt( ((LUMINANCE_WEIGHT * Y) * (LUMINANCE_WEIGHT * Y)) + (Cb * Cb) + (Cr * Cr) );
	}
	
	bool IsPixEqual(const vec3 pixA, const vec3 pixB)
	{
		return (DistYCbCr(pixA, pixB) < EQUAL_COLOR_TOLERANCE);
	}
	
	bool IsBlendingNeeded(const ivec4 blend)
	{
		return any(notEqual(blend, ivec4(BLEND_NONE)));
	}
	
	//---------------------------------------
	// Input Pixel Mapping:    --|21|22|23|--
	//                         19|06|07|08|09
	//                         18|05|00|01|10
	//                         17|04|03|02|11
	//                         --|15|14|13|--
	//
	// Output Pixel Mapping: 20|21|22|23|24|25
	//                       19|06|07|08|09|26
	//                       18|05|00|01|10|27
	//                       17|04|03|02|11|28
	//                       16|15|14|13|12|29
	//                       35|34|33|32|31|30

void main()
{
vec2 f = fract(vTexCoord.xy * SourceSize.xy);

	//---------------------------------------
	// Input Pixel Mapping:  20|21|22|23|24
	//                       19|06|07|08|09
	//                       18|05|00|01|10
	//                       17|04|03|02|11
	//                       16|15|14|13|12
  
	vec3 src[25];
  
	src[21] = COMPAT_TEXTURE(Source, t1.xw).rgb;
	src[22] = COMPAT_TEXTURE(Source, t1.yw).rgb;
	src[23] = COMPAT_TEXTURE(Source, t1.zw).rgb;
	src[ 6] = COMPAT_TEXTURE(Source, t2.xw).rgb;
	src[ 7] = COMPAT_TEXTURE(Source, t2.yw).rgb;
	src[ 8] = COMPAT_TEXTURE(Source, t2.zw).rgb;
	src[ 5] = COMPAT_TEXTURE(Source, t3.xw).rgb;
	src[ 0] = COMPAT_TEXTURE(Source, t3.yw).rgb;
	src[ 1] = COMPAT_TEXTURE(Source, t3.zw).rgb;
	src[ 4] = COMPAT_TEXTURE(Source, t4.xw).rgb;
	src[ 3] = COMPAT_TEXTURE(Source, t4.yw).rgb;
	src[ 2] = COMPAT_TEXTURE(Source, t4.zw).rgb;
	src[15] = COMPAT_TEXTURE(Source, t5.xw).rgb;
	src[14] = COMPAT_TEXTURE(Source, t5.yw).rgb;
	src[13] = COMPAT_TEXTURE(Source, t5.zw).rgb;
	src[19] = COMPAT_TEXTURE(Source, t6.xy).rgb;
	src[18] = COMPAT_TEXTURE(Source, t6.xz).rgb;
	src[17] = COMPAT_TEXTURE(Source, t6.xw).rgb;
	src[ 9] = COMPAT_TEXTURE(Source, t7.xy).rgb;
	src[10] = COMPAT_TEXTURE(Source, t7.xz).rgb;
	src[11] = COMPAT_TEXTURE(Source, t7.xw).rgb;
	
		float v[9];
		v[0] = reduce(src[0]);
		v[1] = reduce(src[1]);
		v[2] = reduce(src[2]);
		v[3] = reduce(src[3]);
		v[4] = reduce(src[4]);
		v[5] = reduce(src[5]);
		v[6] = reduce(src[6]);
		v[7] = reduce(src[7]);
		v[8] = reduce(src[8]);
		
		ivec4 blendResult = ivec4(BLEND_NONE);
		
		// Preprocess corners
		// Pixel Tap Mapping: --|--|--|--|--
		//                    --|--|07|08|--
		//                    --|05|00|01|10
		//                    --|04|03|02|11
		//                    --|--|14|13|--
		// Corner (1, 1)
		if ( ((v[0] == v[1] && v[3] == v[2]) || (v[0] == v[3] && v[1] == v[2])) == false)
		{
			float dist_03_01 = DistYCbCr(src[ 4], src[ 0]) + DistYCbCr(src[ 0], src[ 8]) + DistYCbCr(src[14], src[ 2]) + DistYCbCr(src[ 2], src[10]) + (4.0 * DistYCbCr(src[ 3], src[ 1]));
			float dist_00_02 = DistYCbCr(src[ 5], src[ 3]) + DistYCbCr(src[ 3], src[13]) + DistYCbCr(src[ 7], src[ 1]) + DistYCbCr(src[ 1], src[11]) + (4.0 * DistYCbCr(src[ 0], src[ 2]));
			bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_03_01) < dist_00_02;
			blendResult[2] = ((dist_03_01 < dist_00_02) && (v[0] != v[1]) && (v[0] != v[3])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
		}

		// Pixel Tap Mapping: --|--|--|--|--
		//                    --|06|07|--|--
		//                    18|05|00|01|--
		//                    17|04|03|02|--
		//                    --|15|14|--|--
		// Corner (0, 1)
		if ( ((v[5] == v[0] && v[4] == v[3]) || (v[5] == v[4] && v[0] == v[3])) == false)
		{
			float dist_04_00 = DistYCbCr(src[17], src[ 5]) + DistYCbCr(src[ 5], src[ 7]) + DistYCbCr(src[15], src[ 3]) + DistYCbCr(src[ 3], src[ 1]) + (4.0 * DistYCbCr(src[ 4], src[ 0]));
			float dist_05_03 = DistYCbCr(src[18], src[ 4]) + DistYCbCr(src[ 4], src[14]) + DistYCbCr(src[ 6], src[ 0]) + DistYCbCr(src[ 0], src[ 2]) + (4.0 * DistYCbCr(src[ 5], src[ 3]));
			bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_05_03) < dist_04_00;
			blendResult[3] = ((dist_04_00 > dist_05_03) && (v[0] != v[5]) && (v[0] != v[3])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
		}
		
		// Pixel Tap Mapping: --|--|22|23|--
		//                    --|06|07|08|09
		//                    --|05|00|01|10
		//                    --|--|03|02|--
		//                    --|--|--|--|--
		// Corner (1, 0)
		if ( ((v[7] == v[8] && v[0] == v[1]) || (v[7] == v[0] && v[8] == v[1])) == false)
		{
			float dist_00_08 = DistYCbCr(src[ 5], src[ 7]) + DistYCbCr(src[ 7], src[23]) + DistYCbCr(src[ 3], src[ 1]) + DistYCbCr(src[ 1], src[ 9]) + (4.0 * DistYCbCr(src[ 0], src[ 8]));
			float dist_07_01 = DistYCbCr(src[ 6], src[ 0]) + DistYCbCr(src[ 0], src[ 2]) + DistYCbCr(src[22], src[ 8]) + DistYCbCr(src[ 8], src[10]) + (4.0 * DistYCbCr(src[ 7], src[ 1]));
			bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_07_01) < dist_00_08;
			blendResult[1] = ((dist_00_08 > dist_07_01) && (v[0] != v[7]) && (v[0] != v[1])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
		}
		
		// Pixel Tap Mapping: --|21|22|--|--
		//                    19|06|07|08|--
		//                    18|05|00|01|--
		//                    --|04|03|--|--
		//                    --|--|--|--|--
		// Corner (0, 0)
		if ( ((v[6] == v[7] && v[5] == v[0]) || (v[6] == v[5] && v[7] == v[0])) == false)
		{
			float dist_05_07 = DistYCbCr(src[18], src[ 6]) + DistYCbCr(src[ 6], src[22]) + DistYCbCr(src[ 4], src[ 0]) + DistYCbCr(src[ 0], src[ 8]) + (4.0 * DistYCbCr(src[ 5], src[ 7]));
			float dist_06_00 = DistYCbCr(src[19], src[ 5]) + DistYCbCr(src[ 5], src[ 3]) + DistYCbCr(src[21], src[ 7]) + DistYCbCr(src[ 7], src[ 1]) + (4.0 * DistYCbCr(src[ 6], src[ 0]));
			bool dominantGradient = (DOMINANT_DIRECTION_THRESHOLD * dist_05_07) < dist_06_00;
			blendResult[0] = ((dist_05_07 < dist_06_00) && (v[0] != v[5]) && (v[0] != v[7])) ? ((dominantGradient) ? BLEND_DOMINANT : BLEND_NORMAL) : BLEND_NONE;
		}
		
		vec3 dst[16];
		dst[ 0] = src[0];
		dst[ 1] = src[0];
		dst[ 2] = src[0];
		dst[ 3] = src[0];
		dst[ 4] = src[0];
		dst[ 5] = src[0];
		dst[ 6] = src[0];
		dst[ 7] = src[0];
		dst[ 8] = src[0];
		dst[ 9] = src[0];
		dst[10] = src[0];
		dst[11] = src[0];
		dst[12] = src[0];
		dst[13] = src[0];
		dst[14] = src[0];
		dst[15] = src[0];
		
		// Scale pixel
		if (IsBlendingNeeded(blendResult) == true)
		{
			float dist_01_04 = DistYCbCr(src[1], src[4]);
			float dist_03_08 = DistYCbCr(src[3], src[8]);
			bool haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[4]) && (v[5] != v[4]);
			bool haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[8]) && (v[7] != v[8]);
			bool needBlend = (blendResult[2] != BLEND_NONE);
			bool doLineBlend = (  blendResult[2] >= BLEND_DOMINANT ||
							   ((blendResult[1] != BLEND_NONE && !IsPixEqual(src[0], src[4])) ||
								 (blendResult[3] != BLEND_NONE && !IsPixEqual(src[0], src[8])) ||
								 (IsPixEqual(src[4], src[3]) && IsPixEqual(src[3], src[2]) && IsPixEqual(src[2], src[1]) && IsPixEqual(src[1], src[8]) && IsPixEqual(src[0], src[2]) == false) ) == false );
			
			vec3 blendPix = ( DistYCbCr(src[0], src[1]) <= DistYCbCr(src[0], src[3]) ) ? src[1] : src[3];
			dst[ 2] = mix(dst[ 2], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? ((haveSteepLine) ? 1.0/3.0 : 0.25) : ((haveSteepLine) ? 0.25 : 0.00)) : 0.00);
			dst[ 9] = mix(dst[ 9], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.25 : 0.00);
			dst[10] = mix(dst[10], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.75 : 0.00);
			dst[11] = mix(dst[11], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.00 : ((haveShallowLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[12] = mix(dst[12], blendPix, (needBlend) ? ((doLineBlend) ? 1.00 : 0.6848532563) : 0.00);
			dst[13] = mix(dst[13], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.00 : ((haveSteepLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[14] = mix(dst[14], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.75 : 0.00);
			dst[15] = mix(dst[15], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.25 : 0.00);
			
			dist_01_04 = DistYCbCr(src[7], src[2]);
			dist_03_08 = DistYCbCr(src[1], src[6]);
			haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[2]) && (v[3] != v[2]);
			haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[6]) && (v[5] != v[6]);
			needBlend = (blendResult[1] != BLEND_NONE);
			doLineBlend = (  blendResult[1] >= BLEND_DOMINANT ||
						  !((blendResult[0] != BLEND_NONE && !IsPixEqual(src[0], src[2])) ||
							(blendResult[2] != BLEND_NONE && !IsPixEqual(src[0], src[6])) ||
							(IsPixEqual(src[2], src[1]) && IsPixEqual(src[1], src[8]) && IsPixEqual(src[8], src[7]) && IsPixEqual(src[7], src[6]) && !IsPixEqual(src[0], src[8])) ) );
			
			blendPix = ( DistYCbCr(src[0], src[7]) <= DistYCbCr(src[0], src[1]) ) ? src[7] : src[1];
			dst[ 1] = mix(dst[ 1], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? ((haveSteepLine) ? 1.0/3.0 : 0.25) : ((haveSteepLine) ? 0.25 : 0.00)) : 0.00);
			dst[ 6] = mix(dst[ 6], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.25 : 0.00);
			dst[ 7] = mix(dst[ 7], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.75 : 0.00);
			dst[ 8] = mix(dst[ 8], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.00 : ((haveShallowLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[ 9] = mix(dst[ 9], blendPix, (needBlend) ? ((doLineBlend) ? 1.00 : 0.6848532563) : 0.00);
			dst[10] = mix(dst[10], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.00 : ((haveSteepLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[11] = mix(dst[11], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.75 : 0.00);
			dst[12] = mix(dst[12], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.25 : 0.00);

			dist_01_04 = DistYCbCr(src[5], src[8]);
			dist_03_08 = DistYCbCr(src[7], src[4]);
			haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[8]) && (v[1] != v[8]);
			haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[4]) && (v[3] != v[4]);
			needBlend = (blendResult[0] != BLEND_NONE);
			doLineBlend = (  blendResult[0] >= BLEND_DOMINANT ||
						  !((blendResult[3] != BLEND_NONE && !IsPixEqual(src[0], src[8])) ||
							(blendResult[1] != BLEND_NONE && !IsPixEqual(src[0], src[4])) ||
							(IsPixEqual(src[8], src[7]) && IsPixEqual(src[7], src[6]) && IsPixEqual(src[6], src[5]) && IsPixEqual(src[5], src[4]) && !IsPixEqual(src[0], src[6])) ) );
			
			blendPix = ( DistYCbCr(src[0], src[5]) <= DistYCbCr(src[0], src[7]) ) ? src[5] : src[7];
			dst[ 0] = mix(dst[ 0], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? ((haveSteepLine) ? 1.0/3.0 : 0.25) : ((haveSteepLine) ? 0.25 : 0.00)) : 0.00);
			dst[15] = mix(dst[15], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.25 : 0.00);
			dst[ 4] = mix(dst[ 4], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.75 : 0.00);
			dst[ 5] = mix(dst[ 5], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.00 : ((haveShallowLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[ 6] = mix(dst[ 6], blendPix, (needBlend) ? ((doLineBlend) ? 1.00 : 0.6848532563) : 0.00);
			dst[ 7] = mix(dst[ 7], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.00 : ((haveSteepLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[ 8] = mix(dst[ 8], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.75 : 0.00);
			dst[ 9] = mix(dst[ 9], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.25 : 0.00);
			
			
			dist_01_04 = DistYCbCr(src[3], src[6]);
			dist_03_08 = DistYCbCr(src[5], src[2]);
			haveShallowLine = (STEEP_DIRECTION_THRESHOLD * dist_01_04 <= dist_03_08) && (v[0] != v[6]) && (v[7] != v[6]);
			haveSteepLine   = (STEEP_DIRECTION_THRESHOLD * dist_03_08 <= dist_01_04) && (v[0] != v[2]) && (v[1] != v[2]);
			needBlend = (blendResult[3] != BLEND_NONE);
			doLineBlend = (  blendResult[3] >= BLEND_DOMINANT ||
						  !((blendResult[2] != BLEND_NONE && !IsPixEqual(src[0], src[6])) ||
							(blendResult[0] != BLEND_NONE && !IsPixEqual(src[0], src[2])) ||
							(IsPixEqual(src[6], src[5]) && IsPixEqual(src[5], src[4]) && IsPixEqual(src[4], src[3]) && IsPixEqual(src[3], src[2]) && !IsPixEqual(src[0], src[4])) ) );
			
			blendPix = ( DistYCbCr(src[0], src[3]) <= DistYCbCr(src[0], src[5]) ) ? src[3] : src[5];
			dst[ 3] = mix(dst[ 3], blendPix, (needBlend && doLineBlend) ? ((haveShallowLine) ? ((haveSteepLine) ? 1.0/3.0 : 0.25) : ((haveSteepLine) ? 0.25 : 0.00)) : 0.00);
			dst[12] = mix(dst[12], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.25 : 0.00);
			dst[13] = mix(dst[13], blendPix, (needBlend && doLineBlend && haveSteepLine) ? 0.75 : 0.00);
			dst[14] = mix(dst[14], blendPix, (needBlend) ? ((doLineBlend) ? ((haveSteepLine) ? 1.00 : ((haveShallowLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[15] = mix(dst[15], blendPix, (needBlend) ? ((doLineBlend) ? 1.00 : 0.6848532563) : 0.00);
			dst[ 4] = mix(dst[ 4], blendPix, (needBlend) ? ((doLineBlend) ? ((haveShallowLine) ? 1.00 : ((haveSteepLine) ? 0.75 : 0.50)) : 0.08677704501) : 0.00);
			dst[ 5] = mix(dst[ 5], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.75 : 0.00);
			dst[ 6] = mix(dst[ 6], blendPix, (needBlend && doLineBlend && haveShallowLine) ? 0.25 : 0.00);
		}
		
		vec3 res = mix( mix( mix( mix(dst[ 6], dst[ 7], step(0.25, f.x)), mix(dst[ 8], dst[ 9], step(0.75, f.x)), step(0.50, f.x)),
		                             mix( mix(dst[ 5], dst[ 0], step(0.25, f.x)), mix(dst[ 1], dst[10], step(0.75, f.x)), step(0.50, f.x)), step(0.25, f.y)),
		                        mix( mix( mix(dst[ 4], dst[ 3], step(0.25, f.x)), mix(dst[ 2], dst[11], step(0.75, f.x)), step(0.50, f.x)),
		                             mix( mix(dst[15], dst[14], step(0.25, f.x)), mix(dst[13], dst[12], step(0.75, f.x)), step(0.50, f.x)), step(0.75, f.y)),
		                                                                                                                                    step(0.50, f.y));
								 
   FragColor = vec4(res, 1.0);
} 